1 ################################################################################
2 # Thelp DDisplay command help
4 help [topic [subtopic]]
7 The help command displays help on commands and their usage.
9 In command help, a term enclosed with <...> indicates a value as
10 described by the term. A term enclosed with [...] is optional,
11 and may not be required by all forms of the command.
13 Some commands may not be available. Use the '?' command to list
14 most available commands.
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17 # T? DList available commands
21 Lists all available commands.
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24 # Tautoboot DBoot after a delay
26 autoboot [<delay> [<prompt>]]
28 Displays <prompt> or a default prompt, and counts down <delay> seconds
29 before attempting to boot. If <delay> is not specified, the default
32 ################################################################################
33 # Tboot DBoot immediately
35 boot [<kernelname>] [-<arg> ...]
37 Boot the system. If arguments are specified, they are added to the
38 arguments for the kernel. If <kernelname> is specified, and a kernel
39 has not already been loaded, it will be booted instead of the default
42 ################################################################################
43 # Tbcachestat DGet disk block cache stats
47 Displays statistics about disk cache usage. For depuration only.
49 ################################################################################
50 # Techo DEcho arguments
54 Emits <message>, with no trailing newline if -n is specified. This is
55 most useful in conjunction with scripts and the '@' line prefix.
57 Variables are substituted by prefixing them with $, eg.
59 echo Current device is $currdev
61 will print the current device.
63 ################################################################################
64 # Tload DLoad a kernel or module
66 load [-t <type>] <filename>
68 Loads the module contained in <filename> into memory. If no other
69 modules are loaded, <filename> must be a kernel or the command will
72 If -t is specified, the module is loaded as raw data of <type>, for
73 later use by the kernel or other modules. <type> may be any string.
75 ################################################################################
80 Displays a listing of files in the directory <path>, or the root
81 directory of the current device if <path> is not specified.
83 The -l argument displays file sizes as well; the process of obtaining
84 file sizes on some media may be very slow.
86 ################################################################################
87 # Tlsdev DList devices
91 List all of the devices from which it may be possible to load modules.
92 If -v is specified, print more details.
94 ################################################################################
95 # Tlsmod DList modules
99 List loaded modules. If [-v] is specified, print more details.
101 ################################################################################
104 more <filename> [<filename> ...]
106 Show contents of text files. When displaying the contents of more,
107 than one file, if the user elects to quit displaying a file, the
108 remaining files will not be shown.
110 ################################################################################
111 # Tpnpscan DScan for PnP devices
115 Scan for Plug-and-Play devices. This command is normally automatically
116 run as part of the boot process, in order to dynamically load modules
117 required for system operation.
119 If the -v argument is specified, details on the devices found will
122 ################################################################################
123 # Tset DSet a variable
126 set <variable name>=<value>
128 The set command is used to set variables.
130 ################################################################################
131 # Tset Sautoboot_delay DSet the default autoboot delay
133 set autoboot_delay=<value>
135 Sets the default delay for the autoboot command to <value> seconds.
137 ################################################################################
138 # Tset Sbootfile DSet the default boot file set
140 set bootfile=<filename>[;<filename>...]
142 Sets the default set of kernel boot filename(s). It may be overridden
143 by setting the bootfile variable to a semicolon-separated list of
144 filenames, each of which will be searched for in the module_path
145 directories. The default bootfile set is "kernel".
147 ################################################################################
148 # Tset Sboot_askname DPrompt for root device
152 Instructs the kernel to prompt the user for the name of the root device
153 when the kernel is booted.
155 ################################################################################
156 # Tset Sboot_cdrom DMount root file system from CD-ROM
160 Instructs the kernel to try to mount the root file system from CD-ROM.
162 ################################################################################
163 # Tset Sboot_ddb DDrop to the kernel debugger (DDB)
167 Instructs the kernel to start in the DDB debugger, rather than
168 proceeding to initialize when booted.
170 ################################################################################
171 # Tset Sboot_gdb DSelect gdb-remote mode for the kernel debugger
175 Selects gdb-remote mode for the kernel debugger by default.
177 ################################################################################
178 # Tset Sboot_multicons DUse multiple consoles
182 Enables multiple console support in the kernel early on boot.
183 In a running system, console configuration can be manipulated
184 by the conscontrol(8) utility.
186 ################################################################################
187 # Tset Sboot_serial DUse serial console
191 Force the use of a serial console even when an internal console
194 ################################################################################
195 # Tset Sboot_single DStart system in single-user mode
199 Prevents the kernel from initiating a multi-user startup; instead,
200 a single-user mode will be entered when the kernel has finished
203 ################################################################################
204 # Tset Sboot_verbose DVerbose boot messages
208 Setting this variable causes extra debugging information to be printed
209 by the kernel during the boot phase.
211 ################################################################################
212 # Tset Sconsole DSet the current console
214 set console[=<value>]
216 Sets the current console. If <value> is omitted, a list of valid
217 consoles will be displayed.
219 ################################################################################
220 # Tset Scurrdev DSet the current device
224 Selects the default device. Syntax for devices is odd.
226 ################################################################################
227 # Tset Sinit_path DSet the list of init candidates
229 set init_path=<path>[:<path>...]
231 Sets the list of binaries which the kernel will try to run as initial
235 ################################################################################
236 # Tset Smodule_path DSet the module search path
238 set module_path=<path>[;<path>...]
240 Sets the list of directories which will be searched in for modules
241 named in a load command or implicitly required by a dependency. The
242 default module_path is "/boot/modules" with the kernel directory
245 ################################################################################
246 # Tset Sprompt DSet the command prompt
250 The command prompt is displayed when the loader is waiting for input.
251 Variable substitution is performed on the prompt. The default
252 prompt can be set with:
254 set prompt=\${interpret}
256 ################################################################################
257 # Tset Srootdev DSet the root filesystem
261 By default the value of $currdev is used to set the root filesystem
262 when the kernel is booted. This can be overridden by setting
265 ################################################################################
266 # Tset Stunables DSet kernel tunable values
268 Various kernel tunable parameters can be overridden by specifying new
269 values in the environment.
271 set kern.ipc.nmbclusters=<value> NMBCLUSTERS
273 Set the number of mbuf clusters to be allocated. The value
274 cannot be set below the default determined when the kernel
277 set kern.ipc.nsfbufs=<value> NSFBUFS
279 Set the number of sendfile buffers to be allocated. This
280 overrides the value determined when the kernel was compiled.
282 set vm.kmem_size=<value> VM_KMEM_SIZE
284 Sets the size of kernel memory (bytes). This overrides
285 the value determined when the kernel was compiled.
287 set machdep.disable_mtrrs=1
289 Disable the use of i686 MTRRs (i386 only)
291 set net.inet.tcp.tcbhashsize=<value> TCBHASHSIZE
293 Overrides the compile-time set value of TCBHASHSIZE or
294 the preset default of 512. Must be a power of 2.
296 hw.syscons.sc_no_suspend_vtswitch=<value>
298 Disable VT switching on suspend.
300 value is 0 (default) or non-zero to enable.
302 set hw.physmem=<value> MAXMEM (i386 only)
304 Limits the amount of physical memory space available to
305 the system to <value> bytes. <value> may have a k, M or G
306 suffix to indicate kilobytes, megabytes and gigabytes
307 respectively. Note that the current i386 architecture
308 limits this value to 4GB.
310 On systems where memory cannot be accurately probed,
311 this option provides a hint as to the actual size of
312 system memory (which will be tested before use).
314 set hw.{acpi,pci}.host_start_mem=<value>
316 Sets the lowest address that the pci code will assign
317 when it doesn't have other information about the address
318 to assign (like from a pci bridge). This is only useful
319 in older systems without a pci bridge. Also, it only
320 impacts devices that the BIOS doesn't assign to, typically
321 CardBus bridges. The default <value> is 0x80000000, but
322 some systems need values like 0xf0000000, 0xfc000000 or
323 0xfe000000 may be suitable for older systems (the older
324 the system, the higher the number typically should be).
326 set hw.pci.enable_io_modes=<value>
328 Enable PCI resources which are left off by some BIOSes
329 or are not enabled correctly by the device driver.
331 value is 1 (default), but this may cause problems with
332 some peripherals. Set to 0 to disable.
334 ################################################################################
335 # Tshow DShow the values of variables
339 Displays the value of <variable>, or all variables if not specified.
340 Multiple paths can be separated with a semicolon.
342 ################################################################################
343 # Tinclude DRead commands from a script file
345 include <filename> [<filename> ...]
347 The entire contents of <filename> are read into memory before executing
348 commands, so it is safe to source a file from removable media.
350 ################################################################################
351 # Tread DRead input from the terminal
353 read [-t <value>] [-p <prompt>] [<variable name>]
355 The read command reads a line of input from the terminal. If the
356 -t argument is specified, it will return nothing if no input has been
357 received after <value> seconds. (Any keypress will cancel the
360 If -p is specified, <prompt> is printed before reading input. No
361 newline is emitted after the prompt.
363 If a variable name is supplied, the variable is set to the value read,
364 less any terminating newline.
366 ################################################################################
367 # Tunload DRemove all modules from memory
371 This command removes any kernel and all loaded modules from memory.
373 ################################################################################
374 # Tunset DUnset a variable
376 unset <variable name>
378 If allowed, the named variable's value is discarded and the variable
381 ################################################################################